Just go to your service providers store and talk to them they know! O_O
Same thing happened to me drove me crazy and I called Optus with my home phone and asked about PUK codes, they told me my PUK code and my phone worked and they were very help full the guy also repeated it about 5 times while I was trying to put it in and then decided to writing it down.
which service provider u r using ?
for.ex. if you are using vodafone and your sim is blocked then just take another vodafone sim of anyone may be of your friend call vodafone care he will ask you about last recharge and name on which sim is registered and a code on the sim card he will give you puk code
there is no need to go to shop for this reason
if you have dilled wrong puk code more than three times you definitely have to go to care